Use the drop-down menu and pick "All amazon items sorted by price" then go into the Filters and toggle on the "Add-on Only" option and scroll down to departments and pick a category :)
@tielknight, thank you for stepping in with a response while I was away from the site! @Zain, I like the idea of browsing myself, and most often I use the steps describe by @tielknight to accomplish it, but I agree it would be nice to have it as a standalone feature. When (if) I ever get around to rolling out a v2 of the site I will think of a way to introduce it as an independent use case. Thanks for writing!